What exactly do I need to add to my system to just have VC video input turned off - OR - the VC output blacked out when CV input is received ?

I have Visual Cortex, and Sensory Translator, and I’m getting nice effects with just those, mixed with some digital video, and CCTV cam input, but I want it to be that the video input - live camera for example - is switched off/ blacked out unless receiving signal.

First question is - is there any way of doing this with what I have (I can’t think of a way) , or if not, then what would be the best module to go for next for next. Doorway? Staircase?

I’m not sure I understand what your signal flow is, it sounds like maybe:

Camera -> VC Input Decoder

VC decoder -> VC Colorizer/Compositor Ch. A

Something else -> VC Colorizer/Compositor Ch. B?

VC output encoder -> Display

That is, you are compositing 2 inputs, and you want the output to be blank when the camera input stops, rather than showing what compositor channel B is being fed? If that’s right, I think you can accomplish this if the compositing mode is set to Multiply, and the keyer slider is all the way to the left. This should make it so both channels must have positive luma content at some point on the screen for anything to show up there. Note that if Ch B is in Negative mode you will get white output in this case instead.

As far as what to get next, it depends a bit on what you want to do. Both Doorway and Staircase are powerful processors for camera signals. Quickly you may find you want some oscillators (Prismatic Ray, Fortress) to create more complex pattern elements than are achievable with VC ramps alone, and modulate CV inputs on other modules, and mixers (Passage) to combine video-rate elements with your envelopes from Sensory Translator.